Individually, they are both very beautiful combinations. (Especially HarveyAngelo as both pieces are names that I favor).

On a personal level, I would only use one (Angelo/Angela) just because it's a little much. However, I don't think that there's anything too terrible about using them for twins. They would tucked away in the middle and therefore, not something the kids would have to deal with on a daily basis. The pair, Harvey and Olivia, sound equally classic and polished as well as sleek and modern. I like the idea of a secret connection for twins in the middle slot though.

I would probably try for a different version of Angela/o for one of the twins. I think both is a little OTT. I think the closest I would get would be Angelo and Angeli. (at least the endings feel less similar).

I like Harvey and Olivia as a pair. There's a subtle connection (6 letters, includes the letter V) but without being too 'twinny', if that makes sense. I think the middle names are far too close, though. I'd change Olivia's to something else, it feels a bit off with both names ending in the -a sound.